The document describes the evolution of the Z Hook towel drying design. It started as an ABS plastic 3D printed design, but that would be too expensive to produce. Various redesigns were attempted to make it cheaper to produce, including thinner plastic, parabolic shapes, and adding angled pieces. CNC machining was also considered but couldn't fabricate the designs. The designer then experimented with metal versions, finding a welding company to create an aluminum prototype. Further modifications resulted in a revised design that successfully dries towels 3 times faster than standard hooks.

1. Evolution of the Z Hook Design

2. COMPANY
Spendology is a tech company that uses
psychology and analytics to advance
financial and ecological intelligence.

3. PROBLEM
Standard towel racks and hooks dry bath
towels in approximately 20+ hours* to dry
providing an opportunity for mold & mildew
to grow.
How can towels be dried more quickly?
*Depends on depending on relative humidity, temperature, airflow, room volume, and other variables.

4. SOLUTION
Spread the towel out to maximize surface
area contact of the towel with the air;
enabling convection heating to more
quickly dry the towel.
*Depends on depending on relative humidity, temperature, airflow, room volume, and other variables.

5. EVOLUTION OF THE Z HOOK DESIGN
First CAD Drawing. I thought that I could make this out of ABS plastic and get it 3D
printed.

6. EVOLUTION OF THE Z HOOK DESIGN
I got several quotes for 3D printing. The initial design would take 1 week to print
and cost $1200+ to make one unit. The thinner design cut the cost in half.

7. EVOLUTION OF THE Z HOOK DESIGN
Toying around with a "parabolic design". I didn't get a quote for this.

8. EVOLUTION OF THE Z HOOK DESIGN
I was hoping that this would cost less to make. At this point, I started looking at
plastic-injection molding and CNC Machining.

9. EVOLUTION OF THE Z HOOK DESIGN
Based on the measurements, I didn't think the towel would spread open enough
so I added an angled piece. Still can't get this part machined.

10. EVOLUTION OF THE Z HOOK DESIGN
CNC Machining companies told me they couldn't fabricate the piece. Time to go
back to the drawing board or CAD software in this case...

11. EVOLUTION OF THE Z HOOK DESIGN
I eliminated the flanges and started pricing metals including aluminum and
stainless steel.

12. EVOLUTION OF THE Z HOOK DESIGN
I found a Welding company in Falls Church, VA to develop a prototype for under
$100! I tested the prototype and it worked!

13. EVOLUTION OF THE Z HOOK DESIGN
Time to modify the design so that I can take it to market.

14. EVOLUTION OF THE Z HOOK DESIGN
It looks nice but can a towel hang on it and will it work?

15. EVOLUTION OF THE Z HOOK DESIGN
The revised design works! It dries towels in one-third of the time (approx. 6
hours vs. 20 hours based on conditions).

16. zhook.co